In recent years, touch-panel electronic devices that display various images, such as a text, a photo, a graphic, and a chart, on a panel and allow various operations by touch input to the panel have become popular. The touch-panel electronic devices include, for example, a cellular phone (smartphone), a tablet personal computer (PC), and the like.
More specifically, such an electronic device includes a housing of which the one side is open and a liquid crystal display (LCD) module fixed to the inside of the housing in such a way that a display surface faces to the open side of the housing. The electronic device further includes a touch panel placed so as to be opposed to the LCD module and fit into the open side of the housing.
Elastic dust-proof packing for preventing the intrusion of dust into the LCD module is placed on an outer peripheral part of a side on the side opposite to the touch panel of the LCD module. Furthermore, a flange projecting from an end face of the opening of the housing toward the inside of the opening is formed, and an elastic double-sided tape is attached to the flange. The touch panel is placed to be opposed to the LCD module via the dust-proof packing, and is fixed to the housing via the double-sided tape. An example of conventional technology may be found in Japanese Laid-open Patent Publication No. 2010-218136.
However, the structure of the conventional electronic device is not designed for improving the tracking performance with respect to a pressing operation on the touch panel.
Namely, the dust-proof packing attached to an outer peripheral part of the LCD module is generally made of a relatively-soft material, so the dust-proof packing has a low spring constant and a high (viscoelastic) damping effect. Therefore, when a pressing operation is performed on the touch panel, and the whole touch panel bends, and, after that, the pressing is released, the touch panel may be slow to return to the original position. As a result, for example, when continuous pressing operations are performed on the touch panel, the tracking performance with respect to a pressing operation may be decreased.